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NASA NTRS1977

Very low-Ti mare basalts

Bulk compositions, petrology, and mineralogy of lithic fragments discovered in polished sections of Apollo 17 drill core samples 70007, 70008, and 70009 and Luna 24 soil 24077, 43 are described. The fragments have unambiguous affinities to mare basalts, but are exceptionally low in TiO2 (less than 1.0 wt.% TiO2). Apollo 17 rake sample 78526 is a green glassy rock of similar composition. Together the samples represent a distinct variety of mare basalts. Bulk compositional relationships suggest that they are related to Apollo 15 green glass, but the data do not permit one to discern the precise nature of the relationship. Both fractional crystallization and partial melting models can explain the observed compositional trends.

Taylor, G. J.↗

NASA NTRS1977

Basalts from Mare Crisium

The stratified core sample returned from Mare Crisium by the Luna 24 unmanned space probe is composed primarily of a variety of subophitic to ophitic basalt with very low contents of TiO2 and MgO. This consists of clinopyroxene, calcic plagioclase, olivine, and minor amounts of silica, chromite, ulvoespinel, ilmenite, troilite, apatite, and Fe-metal. Granular metabasalts have the same bulk composition, but mineral phases exhibit less compositional variation. Fine-grained impact melts have similar compositions and are apparently derived from these basalts. It is concluded that the basalts, which are chemically distinct from the very-low-titanium basalts found elsewhere on the moon, represent the local surface flows of Mare Crisium. Sparse fragments of an olivine vitrophyre that is low in TiO2 but high in MgO and approaches the composition of the Apollo 15 green glasses may be derived from patches of dark mantling materials 20 km from the landing site.

Ryder, G.↗

NASA NTRS1978

Silicate spherules from deep-sea sediments - Confirmation of extraterrestrial origin

Silicate spherules larger than 100 microns were extracted from 100 kg of box core samples of Pacific red clay taken in the mid-Pacific at a depth of 5 km, and the concentration of nonvolatile trace elements was determined for three spheres. One of the spheres shows excellent resemblance to C1 chondrite nonvolatile trace-element abundance patterns, and the relative abundances of the other two spheres are also very similar to those of C1 chondrites. One of these two spheres is depleted in Ir and Ru, while the other is depleted for Ni and Cr; possible explanations for the depletions are considered. Since the elemental abundances of the third sphere match the abundances of C1 chondrites, it is suggested that this sphere must be of extraterrestrial origin.

Ganapathy, R.↗

NASA NTRS1979

Emplacement of Fahrenheit crater ejecta at the Luna-24 site

The likelihood that the gabbroic and monomineralic fragments in the Luna-24 soils were excavated during the Fahrenheit cratering event can be assessed by considering the quantity, characteristics, and mode of deposition of Fahrenheit ejecta in the vicinity of the Luna-24 site. The original morphology of Fahrenheit's ejecta deposits is inferred by examining a fresh crater, Lichtenberg B, of a comparable site that formed in a similar type of target material. On the basis of this analogy, a probability of over 80% was calculated that the Luna-24 site was morphologically disturbed by the deposition of Fahrenheit ejecta. The relative abundance, gabbroic composition, and unshocked character of the holocrystalline fragments discovered in the Luna-24 core sample are consistent with the widespread occurrence of Fahrenheit deposits and the characteristics of Fahrenheit ejecta anticipated at the Luna-24 range.

Settle, M.↗

NASA NTRS1983

Evaluation of Antenna Foundation Elastic Modulus

An experiment to measure the elastic deflection of the DSS 14 concrete pedestal under the weight of the antenna was conducted in February 1983 and is compared to a similiar experiment made in 1968. Comparison of the results confirms the decrease in elastic modulus measured on core samples recently taken from the pedestal.

Mcginness, H.↗

NASA NTRS1983

Marine biological controls on atmospheric CO2 and climate

It is argued that the ocean is losing N gas faster than N is being returned to the ocean, and that replenishment of the N supply in the ocean usually occurs during ice ages. Available N from river and estruarine transport and from rainfall after formation by lightning are shown to be at a rate too low to compensate for the 10,000 yr oceanic lifetime of N. Ice sheets advance and transfer moraine N to the ocean, lower the sea levels, erode the ocean beds, promote greater biological productivity, and reduce CO2. Ice core samples have indicated a variability in the atmospheric N content that could be attributed to the ice age scenario.

Mcelroy, M. B.↗

NASA NTRS1984

Salts in the dry valleys of Antartica

The Dry Valleys of Antarctica are examples of polar deserts which are rare geological features on the Earth. Such deserts typically have high salinities associated with their closed-basin waters and on many surficial materials throughout them. In order to examine the possible sources for the salts observed in association with the soils in the Dry Valleys. The chloride and bromide concentrations of the water leachates from 58 soils and core samples were measured. The Cl/Br ratio for seawater is 289 and ratios measured for most of the 58 soils studied (greater than 85% of the soils studied) was larger than the seawater ratio (ratios typically were greater than 1000 and ranged up to 50,000). The enrichment in Cl relative to Br is strong evidence that the alts present within the soils were derived from seawater during ordinary evaporation processes, and not from the deposition of Cl and Br from aerosols or from rock weathering as has often been suggested.

Gibson, E. K., Jr.↗

NASA NTRS1984

Investigation and Rehabilitation to Extend Service Life of DSS-13 Antenna Concrete Foundation

An investigation to establish the cause and, devise a repair technique to maintain the serviceability of the DSS-13 26 meter antenna is described. Core samples are obtained from the concrete and various laboratory tests conducted. In-place nondestructive type tests are also performed. The tests established that the concrete is deteriorating because of alkali aggregate reactivity. This is a phenomenon wherein certain siliceous constituents present in some aggregates react with alkalies in the portland cement to produce a silica gel which, in turn, imbibes water, swells, and cracks the concrete. The scheme consists of a supplemental steel frame friction pile anchored grade beam encircling the existing foundation. This system provides adequate bracing against base shear and overturning due to seismic loading. Larger cracks are sealed using a pressure injected two-component epoxy.

Riewe, A. A., Jr.↗

NASA NTRS1986

Melt-Pressed Films of Insoluble Semicrystalline Polymers

Technique known as "melt pressing" produces films from solid, insoluble, semicrystalline polymers in less than 5 minutes. Amount of crystallinity and possibly final crystal structure of film controlled in process. Induction heating, using gapped toroidal core, melts sample. Toroidal core and capacitor form tuned circuit. Below induction heating toroid, layer of insulation prevents heat transfer from insoluble film to induction heating apparatus.

Tyeryar, J. R.↗

NASA NTRS1984

Atmospheric methane in the recent and ancient atmospheres Concentrations, trends, and interhemispheric gradient

Rasmussen and Khalil (1981) have shown that the concentration of methane is increasing in the earth's atmosphere. A continuing increase of methane may perturb the global environment in the future by warming the earth and leading to more ozone and carbon monoxide in the atmosphere. It appears that the present concentration of methane may be more than twice as high as the natural levels of 150 years ago. An analysis of air bubbles buried long ago in polar ice makes it possible to deduce the concentrations of methane in the old and ancient atmospheres. The present investigation is concerned with the results of an analysis of more than 80 ice core samples, taking into account both polar regions of the earth. The samples range in age from about 100 to nearly 3000 years old. It is found that the concentration of methane started changing significantly about 150 years ago. These findings suggest that the increase of methane is probably indirectly caused by the rapid increase of human population.

Rasmussen, R. A.↗

NASA NTRS1986

Steranes and triterpanes generated from kerogen pyrolysis in the absence and presence of minerals

Changes in the degree of isomerization of steranes and triterpanes during kerogen pyrolysis in the absence or presence of minerals are described. Kerogen from a Monterey Formation diatomite core sample was pyrolyzed under reduced pressure at 300 C for 2-1000 hrs in the presence or absence of calcite, illite, and montmorillonite. It is observed that the extent of isomerization of biomakers in C-20 in 14 alpha(H), 17 alpha(H)-steranes, at C-22 in 17 alpha(H), 21 beta(H)-hopanes and of 17 beta(H), 21 beta(H)-hopanes correlates to early diagenetic stages in rock extracts from sedimentary basins, and faster isomerization for steranes and triterpanes in the bitumen then for those in the kerogen structure are detected. The effects of the minerals on the isomerization reactions are examined; calcite inhibits, and illite and montmorillonite catalyze the reactions.

Tannenbaum, E.↗

NASA NTRS1986

Mars surface science requirements and plan

The requirements for obtaining geological, geochemical, geophysical, and meteorological data on the surface of Mars associated with manned landings were analyzed. Specific instruments were identified and their mass and power requirements estimated. A total of 1 to 5 metric tons, not including masses of drill rigs and surface vehicles, will need to be landed. Power associated only with the scientific instruments is estimated to be 1 to 2 kWe. Requirements for surface rover vehicles were defined and typical exploration traverses during which instruments will be positioned and rock and subsurface core samples obtained were suggested.

Blacic, J. D.↗

NASA NTRS1987

Natural fracture systems on planetary surfaces: Genetic classification and pattern randomness

One method for classifying natural fracture systems is by fracture genesis. This approach involves the physics of the formation process, and it has been used most frequently in attempts to predict subsurface fractures and petroleum reservoir productivity. This classification system can also be applied to larger fracture systems on any planetary surface. One problem in applying this classification system to planetary surfaces is that it was developed for ralatively small-scale fractures that would influence porosity, particularly as observed in a core sample. Planetary studies also require consideration of large-scale fractures. Nevertheless, this system offers some valuable perspectives on fracture systems of any size.

Rossbacher, Lisa A.↗

NASA NTRS1987

Determination of hydrogen abundance in selected lunar soils

Hydrogen was implanted in lunar soil through solar wind activity. In order to determine the feasibility of utilizing this solar wind hydrogen, it is necessary to know not only hydrogen abundances in bulk soils from a variety of locations but also the distribution of hydrogen within a given soil. Hydrogen distribution in bulk soils, grain size separates, mineral types, and core samples was investigated. Hydrogen was found in all samples studied. The amount varied considerably, depending on soil maturity, mineral types present, grain size distribution, and depth. Hydrogen implantation is definitely a surface phenomenon. However, as constructional particles are formed, previously exposed surfaces become embedded within particles, causing an enrichment of hydrogen in these species. In view of possibly extracting the hydrogen for use on the lunar surface, it is encouraging to know that hydrogen is present to a considerable depth and not only in the upper few millimeters. Based on these preliminary studies, extraction of solar wind hydrogen from lunar soil appears feasible, particulary if some kind of grain size separation is possible.

Bustin, Roberta↗

NASA NTRS1987

Prediction of physical workload in reduced gravity environments

The background, development, and application of a methodology to predict human energy expenditure and physical workload in low gravity environments, such as a Lunar or Martian base, is described. Based on a validated model to predict energy expenditures in Earth-based industrial jobs, the model relies on an elemental analysis of the proposed job. Because the job itself need not physically exist, many alternative job designs may be compared in their physical workload. The feasibility of using the model for prediction of low gravity work was evaluated by lowering body and load weights, while maintaining basal energy expenditure. Comparison of model results was made both with simulated low gravity energy expenditure studies and with reported Apollo 14 Lunar EVA expenditure. Prediction accuracy was very good for walking and for cart pulling on slopes less than 15 deg, but the model underpredicted the most difficult work conditions. This model was applied to example core sampling and facility construction jobs, as presently conceptualized for a Lunar or Martian base. Resultant energy expenditures and suggested work-rest cycles were well within the range of moderate work difficulty. Future model development requirements were also discussed.

Goldberg, Joseph H.↗

NASA NTRS1988

Clockwise rotation of the western Mojave Desert

A study of paleomagnetic data from Miocene volcanic rocks in the western Mojave Desert, which suggests about 25 deg of clockwise rotation, is presented. A total of 166 oriented core samples of two types of basalt were taken from 19 sites in the region. After demagnetization to 40 or 60 mT, application of structural corrections, and inversion of reversed sites, the data yielded an average direction of 51.6 deg inclination and 15.6 deg declination. When compared with the expected direction for Miocene rocks for stable North America, the direction for these Mojave rocks shows a clockwise rotation of 23.8 deg + or - 11.3 deg and a flattening of about 2.1 deg, a rotation which agrees in direction with oroclinal bending of the southern Sierra Nevada due to right-lateral shear along the western margin of North America. Most of this rotation is constrained by other paleomagnetic and strucural information to have occurred soon after the sampled basalts were deposited (about 20 Ma) and before about 16 Ma. These clockwise declination anomalies indicate that any subsequent counterclockwise rotation is small and/or compensated by previous clockwise rotation.

Golombek, Matthew P.↗

NASA NTRS1988

Deciphering Martian climatic history using returned samples

By necessity, a Mars sample return mission must sample the upper few meters of the Martian surface. This material was subjected to a wide variety of physical processes. Presently, the most important processes are believed to be wind-driven erosion and deposition, and water ice accumulation at higher latitudes. A sample return mission represents an opportunity to better understand and quantify these important geological processes. By obtaining sample cores at key locations, it may be possible to interpret much of recent Martian climatic history.

Paige, D. A.↗

NASA NTRS1988

Prediction of physical workload in reduced gravity

The background, development, and application of a methodology to predict human energy expenditure and physical workload in low gravity environments, such as a Lunar or Martian base, is described. Based on a validated model to predict energy expenditures in earth-based industrial jobs, the model relies on an elemental analysis of the proposed job. Because the job itself need not physically exist, many alternative job designs may be compared in their physical workload. The feasibility of using the model for prediction of low gravity work was evaluated by lowering body and load weights, while maintaining basal energy expenditure. Comparison of model results was made both with simulated low gravity energy expendiure studies and with reported Apollo 14 Lunar EVA expenditure. Prediction accuracy was very good for walking and for cart pulling on slopes less than 15 deg, but the model underpredicted the most difficult work conditions. This model was applied to example core sampling and facility construction jobs, as presently conceptualized for a Lunar or Martian base. Resultant energy expenditures and suggested work-rest cycles were well within the range of moderate work difficulty. Future model development requirements were also discussed.

Goldberg, Joseph H.↗